Method for separating mixes of different molecules according to size; creates characteristic banding pattern used to identify genes

Electrophoresis is a commonly used method in genetic engineering. Mixes of molecules, mostly proteins or nucleic acids, are loaded into a matrix charged with an electric field. Due to their different size and electric charge the molecules move at different speed, thus separating from each other.

Usually, a gel is used as carrier substance (gel electrophoresis). The molecul mixes are applied and pass through the gel along an electric field. The gel works like a sieve: small molecules can move through it faster than bigger ones. After some time the molecules are located at different sites of the gel and can be visualised by photographic procedures. Each gene creates a typically sequence of "bands".